Static-pressure system for the protection of electrical conductors.



G. N. KERGHER. STATIG PRESSURE SYSTEM PoR TEE PROTECTION 0E ELECTRICAL GONDUCTORS. APPLICATION FILED SEPT. 1,1909.

1 ,082,2'72. Patented Dec. 23, 1913.

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UNITED STATES PATENT OFFICE.

GILBERT N. KERCHER, OF LOS ANGELES, CALIFORNIA, .ASSIGNOR, BY MESNE ASSIGN- MENTS, TO SAFE, VAULT AND PROTECTION COMPANY, OF LOS ANGELES, CALI- FORNIA, A CORPORATION OF CALIFORNIA.

STA'IIC-PRESSURE SYSTEM FOR THE PROTECTION OF ELECTRICAL CONDUCTORS.

To all whom t may concern:

Be it known that I, GILBERT N. KEROHER, a' citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented new and useful Improvements in Static-Pressure Systems for the Protection of Electrical Conductors, of which the following is a specification.

rlhis invention relates to those protection systems in which the conductors are surrounded with a fluid medium under static pressure.

The object of this invention is to provide extremely sensitive means of simple and inexpensive construction not liable to get out of order, whereby tampering with electrical conductors cannot be effected without operatingan alarm, thus making certain the security of alarm systems.

The invention may, in some of its features, be applied to other uses, as, for instance, the protection of walls, bars and barriers against secret rupture.

lThe accompanying drawings illustrate the invention.

Figure 1 is a sectional elevation in diagrammatic form, of an alarm system provided with this invention. Fig. 2 is a crosssection of the static pressure tube and the protected conductors. Fig. 3 is an enlarged sectional detail of the port of the static pressure tube.

The alarm conductors 1, may be covered with insulation 2, and led through one instrument to another instrument for any purpose whatsoever, as for instance, from one telephone to another, or from a guarded structure in a vault to an alarm station. Any number of such conductors may be surrounded by the static pressure tube 3,which may be of metal or other material effective to withn stand the pressure and retain the pressure medium. One end of said static pressure tube 3 communicates with means for maintaining pressure therein under usual conditions. Such means consists of the receiver 4 of a gasometer 5 which may be of the ordinary construction except that it has no gas intake and hermetically incloses the open end of the static pressure tube 3. Saidl receiver may be supplied with a weight 6, and various weights may be employed to produce diEerent pressures in the tube 3. At the Specieation of Letters Patent.

Application filed September 1, 1909.

Patented Dec. 23, 1913.

Serial No. 515,726.

other end of the static pressure tube 3 there is provided a pressure operated electric circuit closer 7, which, in the instance shown, consists of an electrical alarm circuit formed by a fluid trap 8 which may be in the form of a U-tube, partially filled with a charge 9 of quiclrsilver or other conducting stable liquid, forming a seal to retain the pressure medium in the tube 3 there being above the surface of the liquid in the two limbs of the U-tube two contact points 10, 11 of the circuit closing alarm circuit. The static pressure tube 3 is connected with one of the limbs of the U-tube 8, above the surface of the seal, and the other limb is provided with a vent 12 above the level of the liquid charge or seal 9. A contact point 13 is in constant contact with the lliquid and is connected by a conductor 14 with one pole of a battery 15. The contact points 10 and 1l are connected by a conductor 16 through an alarm or signal apparatus, as the bell 17, with the other pole of the battery 15. The static pressure tube 3 is provided with sealed ports 18 through which the conductors 1 of the system are led into and out of the tube. The limb 19 of the U-tube with which the static pressure tube 3 is connected is hermetically sealed, a plug 20 being provided therefor through which the contact point 10 may be inserted. Said contact point may be adjustable through the plug 20, the contact point 10 being threaded and screwed in the plug, and secured by a nut 22.

The pressure induced by the receiver 4 on the medium, which may be air, gas or any other suitable contents of the tube 3, will unbalance the liquid charge 9, and will i maintain different levels of such liquid in the two limbs of the U-tube and such levels will remain constant under constant pressure in the tube 3. In case an attempt is made to reach the conductors 1, which are incased within said tube 3, the tube 3 must be first perforated sufliciently to alter the pressure in said tube 3, thereupon the levels of the surfaces of the liquid charge 9 will vary, thereby causing contact with the contact point 10, whereupon the circuit throu h the alarm apparatus 17 is completed and tie alarm apparatus put into operation.

In order that the system may be highly sensitive in ca'ses of slight perforations through which the pressure medium might escape but slowly, the communication between the static pressure tube 3 and the source of pressure at 4 is eected through a minute orice 23, so that under normal conditions the pressure in the tube will be maintained, but the fluid flowing through the orifice 23 will not be sullicient to supply the fluid discharge through any opening that is liable to be made through the tube 3 of the system.

The space between the contact points and the norinal levels of the surfaces of the liquid charge may be greater or less as desired to aiord the requisite sensitiveness, and the purpose of the contact point 1I in the open or vented liinb of the U-tube is to guard against any tampering by which the pressure in the static pressure tube 3 might be increased. By the construction shown, the static pressure in the tube 3 is confined within certain limits both above and below the intended pressure. If the pressure increases the point ll will contact with the conducting seal, and if the pressure decreases, the point l0 will contact. The amount of pressure in the tube 3 may be varied by increasing or decreasing the weight on the receiver.

I claim:

l. An apparatus of the character described comprising a tube, a gasoineter to seal one end of the tube, a mercury trap to seal the other end of the tube, alarm coni ductors in the tube, contact points in the trap, and an electrically operated signal in circuit with said contact points.

2'. An apparatus of the character described comprising a tube having a minute orifice at one end, a gasoineter herrnetically sealing the tube at the end having the rninute orifice, a fluid trap to hermetically seal the other end of the tube, conductors in the tube, contact points in the trap, and an electrically operated signal in circuit withV said contact points.

3. An apparatus of the character described coniprising a tube having sealed ports between its ends, a gasoineter to seal one end of the tube, a fluid trap to seal the other end of the tube, conductors in the tube and extending through said ports, contact points in the trap, and an electrically operated signal in circuit with said contact points.

4. An apparatus of the character de-li scribed comprising a tube, a gasonieter to seal one end of the tube, and a circuit closing fluid trap to seal the other end of the tube.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 26th day of August, 1909.

GILBERT N. KERCHER.

In presence of- JAMES R. TowNsnND, L. BELLE RICE.

Copies of this patent may be btai'ne'd for ve cents each, by addressing the i Commissioner of Patents, Washington, D; C. 

